Create emphemeral IssueLink if Feedback is present

Create a in-memory IssueLink model if there are no existing IssueLinks
for it and there's an issue_feedback present for the Finding.

See https://gitlab.com/gitlab-org/gitlab/-/issues/223770 for details

ee/app/graphql/resolvers/vulnerabilities/issue_links_resolver.rb

@@ -9,10 +9,16 @@ module Resolvers
                required: false,
                description: 'Filter issue links by link type'
 
-      delegate :issue_links, to: :object, private: true
+      delegate :issue_links, :finding, to: :object, private: true
 
       def resolve(link_type: nil, **)
-        issue_links.by_link_type(link_type)
+        links = issue_links.by_link_type(link_type)
+        return links if links.present? || link_type != 'created'
+
+        issue_feedback = finding.issue_feedback
+        return [] if issue_feedback.blank?
+
+        issue_links.build(issue_id: issue_feedback.id, link_type: :created)
       end
     end
   end

ee/spec/graphql/resolvers/vulnerabilities/issue_links_resolver_spec.rb

@@ -8,8 +8,10 @@ RSpec.describe Resolvers::Vulnerabilities::IssueLinksResolver do
   describe '#resolve' do
     let_it_be(:user) { create(:user) }
     let_it_be(:vulnerability) { create(:vulnerability) }
+    let_it_be(:issue) { create(:issue, project: vulnerability.project) }
+    let_it_be(:vulnerability_feedback) { create(:vulnerability_feedback, issue: issue, feedback_type: 'issue', project: vulnerability.project) }
     let_it_be(:related_issue) { create(:vulnerabilities_issue_link, :related, vulnerability: vulnerability) }
-    let_it_be(:created_issue) { create(:vulnerabilities_issue_link, :created, vulnerability: vulnerability) }
+    let!(:created_issue) { create(:vulnerabilities_issue_link, :created, vulnerability: vulnerability) }
 
     subject { resolve(described_class, obj: vulnerability, args: filters, ctx: { current_user: user }) }
 
@@ -24,6 +26,12 @@ RSpec.describe Resolvers::Vulnerabilities::IssueLinksResolver do
         let(:filters) { { link_type: 'CREATED' } }
 
         it { is_expected.to match_array([created_issue]) }
+
+        context 'and there is no created_issue, but finding has a vulnerability_feedback' do
+          let!(:created_issue) { nil }
+
+          it { is_expected.to all(have_attributes(issue_id: vulnerability_feedback.issue_id, link_type: :created)) }
+        end
       end
 
       context 'when the filter is `RELATED`' do